U.S. patent application number 10/865052 was filed with the patent office on 2004-12-16 for walking stick with flexure mechanism to store and release energy.
Invention is credited to LaRussa, Joseph D., Rudin, Neal H..
Application Number | 20040250845 10/865052 |
Document ID | / |
Family ID | 33514175 |
Filed Date | 2004-12-16 |
United States Patent
Application |
20040250845 |
Kind Code |
A1 |
Rudin, Neal H. ; et
al. |
December 16, 2004 |
Walking stick with flexure mechanism to store and release
energy
Abstract
A walking stick with a flexure spring to store energy from
compression during the user's step, and release of the energy to
aid in propelling the user forward, thereby reducing fatigue and
enabling longer and faster walks.
Inventors: |
Rudin, Neal H.; (Rochester,
NY) ; LaRussa, Joseph D.; (Rochester, NY) |
Correspondence
Address: |
Garold F. Fritz
4325 Lake Road
Williamson
NY
14589-9603
US
|
Family ID: |
33514175 |
Appl. No.: |
10/865052 |
Filed: |
June 10, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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60477913 |
Jun 13, 2003 |
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Current U.S.
Class: |
135/77 |
Current CPC
Class: |
A45B 2009/005 20130101;
A45B 2200/055 20130101; A45B 9/00 20130101; A45B 7/005 20130101;
A45B 9/02 20130101; A61H 3/0277 20130101 |
Class at
Publication: |
135/077 |
International
Class: |
A61F 002/66; A61H
003/02; A45B 009/04 |
Claims
What is claimed is:
1. A walking aid comprising, a straight shaft terminated with a
handgrip at an upper end, and with a curvilinear shaped flexure
spring at a lower end, said curvilinear shaped flexure spring
having a free end, distal from said straight shaft, so that said
free end will contact the surface upon which a person, gripping
said handgrip, is standing, said free end having an attached foot
providing means for preventing said free end from sliding on the
surface upon which said person is standing.
2. The walking aid of claim 1 wherein said curvilinear shaped
flexure spring has a spring constant in the range between 5 and 50
pounds/inch.
3. The walking aid of claim 2 wherein said straight shaft, said
handgrip, and said curvilinear shaped flexure spring are integrally
formed in a single part of a common material.
4. The walking aid of claim 3 wherein said common material
comprises a plurality of layers of a composite material.
5. The walking aid of claim 4 wherein said composite material is
chosen from the group consisting of fiberglass and carbon
fiber.
6. The walking aid of claim 2 wherein said straight shaft, said
handgrip, and said curvilinear shaped flexure spring are separate
parts with means for connecting together.
7. The walking aid of claim 6 wherein said curvilinear shaped
flexure spring comprises a plurality of layers of a composite
material.
8. The walking aid of claim 7 wherein said composite material is
chosen from the group consisting of fiberglass and carbon
fiber.
9. The walking aid of claim 8 wherein said straight shaft further
comprises an upper section and a lower section with means for
connecting said upper section to said lower section so that the
overall length is adjustable.
10. The walking aid of claim 6 wherein said curvilinear shaped
flexure spring is made from a material selected from the group
consisting of a metal, a wood, a plastic, and a ceramic.
11. A walking aid comprising, an L-shaped shaft with a generally
horizontal upper section at approximately 90.degree. to a generally
vertical lower section, said upper section having a
semi-cylindrical arm support, and terminated with a handgrip, said
lower section terminated with a curvilinear shaped flexure spring,
said curvilinear shaped flexure spring having a free end, distal
from said generally vertical lower section, so that said free end
will contact the surface upon which a person, gripping said
handgrip, is standing, said free end having an attached foot
providing means for preventing said free end from sliding on the
surface upon which said person is standing.
12. The walking aid of claim 11 wherein said curvilinear shaped
flexure spring has a spring constant in the range between 5 and 50
pounds/inch.
13. The walking aid of claim 12 wherein said L-shaped shaft, said
handgrip, and said curvilinear shaped flexure spring are integrally
formed in a single part of a common material.
14. The walking aid of claim 13 wherein said common material
comprises a plurality of layers of a composite material.
15. The walking aid of claim 14 wherein said composite material is
chosen from the group consisting of fiberglass and carbon
fiber.
16. The walking aid of claim 12 wherein said L-shaped shaft, said
handgrip, and said curvilinear shaped flexure spring are separate
parts with means for connecting together.
17. The walking aid of claim 16 wherein said curvilinear shaped
flexure spring comprises a plurality of layers of a composite
material.
18. The walking aid of claim 17 wherein said composite material is
chosen from the group consisting of fiberglass and carbon
fiber.
19. The walking aid of claim 18 wherein said L-shaped shaft further
comprises an upper section and a lower section with means for
connecting said upper section to said lower section so that the
overall length is adjustable.
20. The walking aid of claim 16 wherein said curvilinear shaped
flexure spring is made from a material selected from the group
consisting of a metal, a wood, a plastic, and a ceramic.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application, excluding claims 10 and 20, claims the
benefit of U.S. Provisional Application No. 60/477,913 filed Jun.
13, 2003.
FIELD OF THE INVENTION
[0002] The invention relates in general to walking aid sticks and,
more specifically, to a walking stick with a built in flexure
spring to return energy into each step to help propel the user
forward.
BACKGROUND OF THE INVENTION
[0003] Walkers and climbers can benefit from walking sticks that
have the feature of returning kinetic energy that is acquired as
the walking stick compresses in contact with the ground. This
retained energy has the benefit that the users have to expend less
of their own energy moving their legs forward, thus allowing them
to walk or climb further and faster more comfortably and with less
fatigue. Experiencing this advantage, the user will increase their
interest in the activity and become a more active person.
[0004] The use of a walking stick with an energy storage spring for
returning energy to the walker is well known to those familiar with
the art. An example is the use of energy storage springs in foot
prosthesis; particularly those used for athletic purposes. Designs
include that of U.S. Pat. No. 6,007,582 or that in use in the
Flex-foot.RTM., manufactured by Ossur hf of Reykjavik, Iceland.
Examples where a spring mechanism stores and then sequentially
dissipates energy for the sole purpose of cushioning a walking
stick are described in U.S. Pat. No. 6,131,592, U.S. Pat. No.
5,720,474, and FR2617023. These walking sticks utilize a mechanical
device such as a coil spring or cylinder for a spring and do not
make use of the compression of a flexure to return the energy from
the material compressing as a step is taken.
[0005] A published paper entitled "The design of a compliant
composite crutch" by D. Shortell et al. discloses two designs of
crutches using composite materials. The first design utilizes a
metal coil spring embedded in a single unit composite material
crutch. The coil spring compresses under the weight of the user
with a spring force in the range of 90 to 170 lbs. The spring
force, which acts in the vertical direction, is for shock
absorption, not as a forward propelling aid. A second crutch design
utilizes the flexure of the S curve in the shaft of the crutch in
place of the coil spring. The effective springs that are designed
using the composite material in place of the coil spring also
operate in the vertical direction for shock absorption, not as a
forward propelling aid. Another feature of the crutches that are
the subject of the Shortell et al. publication is a rigid armrest
with a grip. These armrests are oriented in the vertical direction
for the purpose of providing the user with more support.
SUMMARY OF THE INVENTION
[0006] In light of the above, the object of the present invention
is to provide a walking stick that absorbs energy in the downward
first motion of a walking stride and then returns the stored energy
to aid in propelling the walker forward in the final forward motion
of the walking stride.
[0007] The walking stick that is the subject of this patent
application utilizes a flexure spring as an extension of the
straight shaft of the stick. The shape and location of the flexure
spring are such that the spring force helps propel the walker
forward. The spring constant of the flexure spring is in the range
of 5 to 50 lbs. per inch of deflection. In the preferred embodiment
the flexure spring is fabricated using composite materials.
[0008] The walking stick of the present invention may be used in a
wide number of applications. Examples include a walking and
climbing stick for hikers, an ambulatory aid for a person
recovering from surgery or otherwise limited in ability to walk, a
substitute for a ski pole for cross country skiing, a pole for use
in roller blading, a hiking stick that will also function as a
canoe paddle, or a walking stick for snow shoeing. It may be a
molded single unit or assembled out of multiple components. As a
molded single unit the flexure spring is integral to the molded
stick. As a stick built of multiple components, the flexure spring
is attached to the straight shaft of the stick and may be
interchangable depending upon the size and weight of the user, or
depending on one of the specific uses listed above.
[0009] The invention, and its objects and advantages, will become
more apparent in the detailed description of the preferred
embodiment presented below.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] In the detailed description of the preferred embodiments of
the invention presented below, reference is made to the
accompanying drawings, in some of which the relative relationships
of the various components are illustrated, it being understood that
orientation of the apparatus may be modified. For clarity of
understanding of the drawings, relative proportions depicted or
indicated of the various elements of which disclosed members are
comprised may not be representative of the actual proportions, and
some of the dimensions may be selectively exaggerated.
[0011] FIG. 1 illustrates a single-piece walking stick.
[0012] FIG. 2 illustrates a multi-piece walking stick.
[0013] FIG. 3 illustrates a multi-piece walking stick with
adjustable length.
[0014] FIG. 4 illustrates a walking stick with a horizontal arm
support.
[0015] FIG. 5 is plot of force versus deflection for two
embodiments of walking sticks of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0016] Referring to FIG. 1, therein is shown a preferred embodiment
of the invention. This walking stick, generally designated by
numeral 10, is molded as a single unit of fiberglass, carbon, or
other composite material. Walking stick 10 includes a straight
shaft 28 terminated at the upper end with a handgrip 14 and at the
lower end with a flexure spring 16. Walking stick 10 may be
constructed of laminated linear fiberglass or other composite
material. In a preferred embodiment walking stick 10 is constructed
of a fiberglass tape such as that manufactured by the Fibreglast
Development Corp. of Brookville, Ohio, USA. Attached to flexure
spring 16, at the point where flexure spring 16 would contact the
walking surface, is a foot 24. The purpose of foot 24 is to prevent
flexure spring 16 from sliding on the walking surface. Foot 24 may
be made from rubber, such as, for example, a section of rubber
tubing, or any other material with a suitable coefficient of
friction with the walking surface.
[0017] Another embodiment of the walking stick of the present
invention is shown in FIG. 2 and designated generally as numeral
30. Walking stick 30 in FIG. 2 includes similar sections as walking
stick 10 in FIG. 1, that is, a straight shaft 26, a handgrip 15,
and a flexure spring 18, but the sections of walking stick 30 are
separate assembled parts instead of molded as a single unit. In the
walking stick 30 embodiment flexure spring 18 is constructed of
laminated linear fiberglass or other composite material. Straight
shaft 26 may also be constructed of laminated linear fiberglass or
other composite material or of any other rigid material such as,
for example, aluminum, steel, stainless steel, or the like.
Handgrip 15 is constructed of hard rubber, wood, or any other
similar material. Flexure spring 18 and handgrip 15 are connected
to opposite ends of straight shaft 26 by pins 19 and 17
respectively. Flexure spring 18 of the walking stick 30 embodiment
also has attached to it a foot 24, the same as in the walking stick
10 embodiment.
[0018] For some sports applications an adjustable length walking
stick is preferred. Referring to FIG. 3, therein is shown a design
of an adjustable length walking stick 40. The walking stick 40
embodiment has the same flexure spring 18 with pin 19, and handgrip
15 with pin 17 as the walking stick 30 embodiment of FIG. 2. The
straight shaft of the walking stick 40 embodiment includes two
telescoping sections 25 and 27. Several means for locking the
adjusted length of sections 25 and 27 are known in the art, one of
which is shown in FIG. 3. Section 25 contains a spring-loaded pin
32 that is pushed into one of a series of holes 34 in section 26 to
secure the desired length of walking stick 40. Other adjustable
means can be used such as the mechanism cited in U.S. Pat. No.
5,769,104.
[0019] FIG. 4 shows another embodiment of the walking stick of the
present invention generally designated by numeral 50. Walking stick
50 embodiment is distinguished by an arm support section 52 at an
approximate 90.degree. angle to the vertical straight shaft 28. Arm
support section 52 has a semi-cylindrical arm support 54 and a
handgrip 56. AA is a cross-section view of semi-cylindrical arm
support 54. Straight vertical shaft 28 and flexure spring 16 with
foot 24 in the walking stick 50 embodiment are the same is in the
walking stick embodiment 10 of FIG. 1. Arm support section 52, with
semi-cylindrical arm support 54, of the walking stick 50 embodiment
is positioned in the horizontal direction, in line with the natural
arm and hand posture used when walking or hiking and helps reduce
arm fatigue on long hikes and especially climbing. Arm support
section 52 with semi-cylindrical arm support 54 and handgrip 56 may
also replace handgrip 15 of the walking stick embodiments of FIGS.
2 and 3, and be molded from plastic. To provide protection for the
walker's hands, handgrip 56 of the walking stick 50 embodiment may
also be surrounded by a molded hand guard.
[0020] FIG. 5 illustrates, for two preferred embodiments of the
walking stick of the present invention, the amount of spring force
as a function of the amount of deflection of the flexure spring.
Curve 50 represents the result for a preferred embodiment walking
stick for a person weighing in the range of 175 to 225 lbs. Curve
52 represents the characteristics of a preferred embodiment hiking
stick for a person weighing in the range of approximately 100 lbs.
Curve 50 indicates that a deflection of 1 inch produces a spring
force of 19 lbs. Similarly curve 52 indicates that a deflection of
1 inch produces a spring force of 10 to 11 lbs. These curves show
that with a deflection greater than 4 inches, the relationship
between deflection and force increases nonlinearly so that when the
walking stick is heavily compressed, large spring forces result.
When the transition to a higher spring force is reached, it is a
signal to the athlete to push off or, in other words, to transfer
his/her weight to the other stick.
[0021] The multi-part embodiments of the walking stick of the
present invention, as illustrated in FIGS. 2 and 3, enable the use
of interchangable flexure springs with different spring force
constants for different weight users, or with different shaped feet
for use on different surfaces. For example, the foot shown in FIGS.
14 may be optimum for use on hard packed or paved surfaces, whereas
a flared, higher surface area foot may be better for use in snow or
mud. An extremely flared foot with very high surface area may serve
double duty as a walking stick and as a canoe paddle.
[0022] The invention has been described in detail with particular
reference to certain preferred embodiments thereof, but it will be
understood that variations and modifications can be effected within
the spirit and scope of the invention.
* * * * *